Answer:
The y-coordinate of the fourth vertex is j.
Explanation:
Since, the diagonals of parallelogram bisect each othe,
That is, the midpoint of one diagonal = the midpoint of the other diagonal,
Here, the consecutive vertices are (h, j), (0, 0), and (k, 0), where h > 0,
Let (x,y) are the coordinates of fourth vertex,
⇒ Midpoint of coordinates (h, j) and (k, 0) = Midpoint of coordinate (0,0) and (x,y)

By comparing the y-coordinates,


Hence, the y-coordinate of the fourth vertex is j.
Second option is correct.